Add all the ingredients except the coriander to a preserving pan. Bring to the boil, then simmer, uncovered, for 1–1¼ hours, stirring from time to time, until the chutney is thick.

Remove from the heat and stir in the coriander.

Ladle into warm, dry jars, filling to the very top and pressing down well. Disperse any air pockets with a skewer or small knife and cover with screw-top lids. Label and leave to mature in a cool, dark place for at least 3 weeks.